Project Blue Book
The U.S. Air Force studied UFOs for 17 years — and 701 cases were never solved.
For seventeen years the U.S. Air Force formally investigated UFO reports under Project Blue Book, collecting over 12,000 cases. It concluded the phenomenon was no threat — yet left 701 cases officially 'unidentified.'
Project Blue Book is the foundational government record of UFO investigation, and it is fully declassified — anyone can read the files today. From 1952 to 1969, the U.S. Air Force systematically collected and analyzed 12,618 UFO reports from across the country.
The project's public conclusion was reassuring: no UFO had ever threatened national security, none represented technology beyond contemporary science, and there was no evidence of extraterrestrial vehicles. On that basis, Blue Book was shut down in 1969.
But the numbers tell a more unsettling story. Of those 12,618 cases, 701 remained classified as genuinely 'unidentified' — not weather, not aircraft, not hoaxes, simply unexplained. Astronomer Dr. J. Allen Hynek, the project's own scientific consultant, grew from skeptic to believer, later accusing the program of existing partly to debunk rather than investigate. He went on to create the 'close encounter' classification system the world still uses.
- ■The full declassified Blue Book archive (National Archives)
- ■701 officially unexplained cases out of 12,618
- ■Dr. J. Allen Hynek's evolution from consultant to critic
The government's own 17-year study closed the books while leaving 701 cases open. Officially: nothing to see. On the record: 701 things it could not explain.